Before distribution, an IC (Integrated Circuit) package is tested for proper functionality. In such testing, the pins on the IC package are coupled to test contacts of a testing system, and various measurements are performed from the test contacts to determine proper functionality.
An example of a IC package handler, within such an integrated circuit testing system, is the Delta Flex Test Handler, Model 1240, available from Delta Design, Inc., San Diego, Calif. Referring to FIG. 1, such an IC package handling system 100 includes an input mechanism 102, a core testing unit 104, and an output mechanism 106. The input mechanism 102 carries the IC packages to be tested into the core testing unit 104 and onto a storage boat 108, already carrying an IC package 110 in FIG. 1. The storage boat 108 carries the integrated circuit package 110 to be tested on a track 112 between the input mechanism 102, the core testing unit 104, and the output mechanism 106. In addition, the storage boat 108 carries the IC package 110 until the IC package reaches a desired temperature for testing.
Within the core testing unit 104, a core picker assembly 114 picks up an IC package from the storage boat 108 for testing. After testing, the core picker assembly 114 places the tested integrated circuit onto an output boat 115 within the output mechanism 106. The core testing unit 104 also includes a temperature control unit 116 for adjusting the temperature within the core testing unit 104 such that the integrated circuit may be tested for various environmental temperatures.
Once the testing of an IC package is complete, the output boat 115 receives the tested IC package from the core picker assembly 114, and the output mechanism 106 carries the tested IC package to a sorting unit 118. When a tested IC package is at the sorting unit 118, each IC package is sorted into a respective bin depending on the results of testing that IC package within the core testing unit 104. For example, if the result of testing an IC package is performance failure, that IC package is placed into a "bad chip" tube 120, and if the result is performance success, the package is placed into a "good chip" tube 122.
The present invention relates to a design for the output mechanism 106. FIG. 2 shows a prior art boat retrieval mechanism 200 for the output mechanism 106 of FIG. 1. The boat retrieval mechanism includes the output boat 115 carrying tested IC packages from the core testing unit 104, and carries the output boat 115 to the sorting unit 118. (Note, that elements having the same reference numeral in FIGS. 1 and 2 refer to the same element.)
Referring to FIG. 2, the prior art boat retrieval mechanism 200 includes a boat carrier 202 which carriers the output boat 115 from the core testing unit 104 after tested IC packages have been placed on the output boat 115. Furthermore, the boat carrier 202 carries the output boat 115 between the core testing unit 104 and the sorting unit 118. A belt 204 coupled to the boat carrier 202 moves the boat carrier 202 back and forth between the core testing unit 104 and the sorting unit 118. A motor 206 drives the belt 204 to move forward and backward from the core testing unit 104 to the sorting unit 118.
To maintain the path of travel of the output boat 115 along a linear path between the core testing unit 104 and the sorting unit 118, four pairs of roller bearings are disposed in that linear path. A first pair includes a first roller bearing 208 and a second roller bearing 210. A second pair includes a third roller bearing 212 and a fourth roller bearing 214. A third pair includes a fifth roller bearing 216 and a sixth roller bearing 218. Finally, a fourth pair includes a seventh roller bearing 220 and an eighth roller bearing 222. These roller bearings roll against a side wall of the boat carrier 202 to maintain the path of travel of the boat carrier 202 along a linear path.
FIG. 3A shows a cross section along line AA of the prior art boat retrieval mechanism 200. (Note, that elements having the same reference numeral in FIGS. 1-3 including FIGS. 3A and 3B refer to the same element.) The third roller bearing 212 is disposed on a first side 302 of the boat carrier 202, and the fourth roller bearing 214 is disposed on a second side 304 of the boat carrier 202. The eight roller bearings 208, 210, 212, 214, 216, 218, 218, 220, and 222 roll along the side walls of the boat carrier 202 and guide the path of the carrier 202 as the carrier 202 travels between those roller bearings.
The positions of the roller bearings 208, 210, 212, 214, 216, 218, 218, 220, and 222 are aligned to guide the boat carrier 202. FIG. 3B shows an example situation when the third roller bearing 212 and the fourth roller bearing 214 are not aligned properly. The third roller bearing 212 is disposed too near the boat carrier 202 on the first side 302, and the fourth roller bearing 214 is disposed too far from the boat carrier 202 on the second side 304. Thus, the third roller bearing 212 is subject to more wear, and may require replacement. The fourth roller bearing 214 may require to be realigned to a position more toward the second side 304 of the boat carrier. However, roller bearing replacement and realignment in the prior art boat retrieval mechanism 200 may be labor intensive and costly.
In addition, in the prior art boat retrieval mechanism 200, the motor 206 may be located near the core testing unit 104. Such a location makes maintenance of the motor inconvenient because the motor is difficult to access due to the framework of the core testing unit 104. Moreover, the prior art boat retrieval mechanism 200 may not have a grounding mechanism for providing a conductive path from the boat carrier 202 to a ground potential. Without a grounding mechanism, an IC package being carried on the output boat 115 may be electrostatically damaged when the output boat 115 carrying that IC package is on the boat carrier 202.